NEW YORK
— From its base in Akron, Ohio, FirstEnergy has the chain saws out as foot patrols finish up the job of looking for sagging trees that may fall on any of their 11,000 miles of high-tension lines.

In Columbus, Ohio, American Electric Power is devising scenarios to train its system controllers how to react to such things as phone lines that won't work, individual power plants that fail, and even the complete collapse of its own huge system.

And in Chicago, Commonwealth Edison is finishing up the job of upgrading transmission lines and substations in the burgeoning southwest part of the city to prevent overloading in the summer heat.

After last summer's blackout, such efforts are now taking on even more significance as the heat starts to build. Companies are increasing training, spending more money on computer software, adding alarms to unmanned substations, and even hiring helicopters to look for weak spots in their high-tension lines. The added diligence, they hope, means that most Americans will get through the summer without a reduction in air conditioning. "We cannot guarantee you will have power, but an outage like last year is highly unlikely," says Bill Brier of the Edison Electric Institute, an industry trade group in Washington.

However, utility executives think it's possible some people may experience a short-term blackout since the utilities will operate more conservatively. If there is even a hint of a local problem that may spread, operators may black out a neighborhood, town, or city to prevent the problem from cascading into something more serious.

Last month the North American Electric Reliability Council (NERC), an industry self-regulatory organization, said it expected the nation to get through the summer without a problem. But it also warned that extremely hot weather and unanticipated equipment problems might cause some glitches.

With the better economy, it is anticipating demand will be 2.5 percent higher than last summer. Consumers may ultimately pay more for their electricity since the price of natural gas, oil, and even coal is higher than last year.

Regulators and task forces spent the winter analyzing what went wrong last Aug. 14 when some 50 million people in eight states lost power. In early April, a US-Canada task force said the problems included computer failures, inadequate training, and lax tree trimming.

Yet even before the report was issued, utilities began scrambling to get ready for this summer. For example, investigators had already found that last year's blackout started at FirstEnergy when some trees sagged onto high-tension lines and their computer system failed to alert operators. Last week, the company had a new computer system up and running.

The company has also had crews walking along most of their transmission lines looking for any vegetation that might interrupt the power flow. "On the corridor, we are very clear [that] the plantings are not allowed to exceed 10 feet in height," says Scott Lowry, director of vegetation management. The company is also trying to manage trees that it thinks may be a threat outside its corridor - which has some customers seeking restraining orders to prevent tree cutting. "It's an emotional issue," says Ralph DiNicola, vice president of communications. "We will work through the courts to clear along the easements, which we believe is in the public interest."

Utilities that were not involved in the blackout last summer are also upgrading their equipment. That's the case with Commonwealth Edison, which is installing sump pumps to prevent water damage to unmanned substations. For the first time, many of the sumps are now hooked up to alarms that go back to control rooms.

"Now, we go out and test these sumps once a month. In the past, we didn't test them at all," says Preston Swafford, a senior vice president. Installing the equipment has been useful, he says. "For example, we've found a lot of wiring that was decayed, and we've made that operable."

Some utilities are even preparing for the unthinkable - another large blackout. At American Electric Power, the operators of its 35,000 miles of transmission lines recently practiced what to do in case of a complete collapse. This included drills on how to restart power plants that have been shut down when the entire grid is not working and learning how to communicate when the phone system is down.